84522.20131010; October 10, 2013

³Measured position corresponds to RA offset of +0.0829 and Dec. offset of –0.436.

⁴All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction.

⁴Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation.

⁵The reference positions for Haumea are those given by JPL Horizon's ephemeris (84522 source file: JPL9; Earth center source file: DE405).

⁶Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 3 years were reduced with respect to stars in the UCAC2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of 84522: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.

Table 1: Prediction Details
84522 Geocentric Mid-time (yyyy month dd hh:mm:ss)	2013 October 10 06:41:53± 00:01:59¹ UT
84522 Minimum Geocentric Separation	0.001± 0.111¹ arcsec
Position Angle (84522 relative to the star; measured north through east)	171.35 degrees
Geocentric Velocity	24.26 km/sec
Occultation Star USNOB R magnitude	16.18²

Table 2: Reference Star Position
Reference star position: (UCAC2, at epoch of event)	RA (h:m:s; J2000)	Dec (d:m:s; J2000)	Notes
84522.20131010 Catalog	02 14 15.9967 ± 0.0970	+24 51 18.427 ± 0.150
84522.20131010 Measured³	02 14 16.0028 ± 0.0034	+24 51 17.992 ± 0.013	From 5 Lowell 42-inch frames
Table 3: Projected KBO Offsets from Reference Ephemeris at the Time of the Event
Body	RA (arcsec)	Dec (arcsec)
84522	0.2107 ± 0.0904	–0.242 ± 0.111	See Notes 5 and 6
³Measured position corresponds to RA offset of +0.0829 and Dec. offset of –0.436. ⁴All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction. ⁴Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation. ⁵The reference positions for Haumea are those given by JPL Horizon's ephemeris (84522 source file: JPL9; Earth center source file: DE405). ⁶Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 3 years were reduced with respect to stars in the UCAC2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of 84522: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.

Site	East Longitude	Latitude	Site Altitude⁶ (km)	Distance⁷ (km)	Velocity (km/s)
CTIO	–70 48 54	–30 09 54	2.215	5268 S.	24.66
Haleakala	–156 15 24	+20 42 24	3.054	2009 N.	24.35
Hartung Boothroyd Observatory	–76 23 04	42 27 29	0.534	1815 N.	24.60
Magdalena Ridge Obs	–107 11 05	+33 58 36	2.219	1433 N.	24.60
McDonald Obs	–104 01 21	+30 40 17	2.076	1005 N.	24.62
SVH	–74 56 45	40 57 41	0.220	1646 N.	24.61
Wallace	–71 29 06	42 36 36	0.107	1806 N.	24.60
Williams	–73 12 06	42 42 42	0.215	1824 N.	24.60
Geocenter	----------	---------	center of Earth	24 N.	24.26

Site	KBO Immersion (UT)⁹	UT Mid-Time	KBO Altitude	Solar Altitude⁹	KBO Emersion (UT)⁹
CTIO	-----------	06:41:27	33	-----------	-----------
Haleakala	-----------	06:45:35	27	-----------	-----------
Hartung Boothroyd Observatory	-----------	06:41:10	70	-----------	-----------
Magdalena Ridge Obs	-----------	06:43:04	70	-----------	-----------
McDonald Obs	-----------	06:42:58	74	-----------	-----------
SVH	-----------	06:41:06	72	-----------	-----------
Wallace	-----------	06:40:54	68	-----------	-----------
Williams	-----------	06:41:00	69	-----------	-----------
Geocenter	06:41:28	06:41:53	-----------	-----------	06:42:18

84522.20131010 Occultation October 10, 2013